i have used a different construction technique with these trees which
requires more polygons than my normal trees.
these trees have a poly count of either 128 or 196 so those of you with
slow machines should probably pass on them or at least be very judicious
in 'planting' them! several people who tested them found them to have
a 'reasonably low to negligible'
impact on frame rates, if used in moderation. don't build forests with
these trees or 'your world' will stop spinning!

to lessening their impact i have added lod versions to each model.
the lod is invoked at 10% of screen height, with a poly count of 50%. it
is noticeable when the image switches from lod to main version, so before
populating your route with this new series you should test them to make
sure you don't find this objectionable or distracting.
i have found that having the base height of the trees, that is, the bottom
of the trunk, slightly above ground level looks better and so i have built
the series in this way. if you prefer them 'planted' in the ground, they
can be lowered into the ground by using the height adjustment tool.

after installation this series will be found in the perfect tall trees
menu of the objects tab.